2001 BMW 520 vs. 2003 BMW 645
To start off, 2003 BMW 645 is newer by 2 year(s). Which means there will be less support and parts availability for 2001 BMW 520. In addition, the cost of maintenance, including insurance, on 2001 BMW 520 would be higher. At 4,398 cc (8 cylinders), 2003 BMW 645 is equipped with a bigger engine. In terms of performance, 2003 BMW 645 (325 HP @ 6100 RPM) has 158 more horse power than 2001 BMW 520. (167 HP @ 6500 RPM) In normal driving conditions, 2003 BMW 645 should accelerate faster than 2001 BMW 520. With that said, vehicle weight also plays an important factor in acceleration. 2003 BMW 645 weights approximately 20 kg more than 2001 BMW 520. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Both vehicles are rear wheel drive (RWD) - it offers better handling in dry conditions; in addition, if you are looking to drift, both vehicles do the job better than front wheel drive vehicles. With that said, do keep in mind that many other factors such as speed and the wear on your tires can also have significant impact on traction and control. Let's talk about torque, 2003 BMW 645 (450 Nm @ 3600 RPM) has 240 more torque (in Nm) than 2001 BMW 520. (210 Nm @ 3500 RPM). This means 2003 BMW 645 will have an easier job in driving up hills or pulling heavy equipment than 2001 BMW 520.
Compare all specifications:
| 2001 BMW 520 | 2003 BMW 645 | |
| Make | BMW | BMW |
| Model | 520 | 645 |
| Year Released | 2001 | 2003 |
| Body Type | Station Wagon | Coupe |
| Engine Position | Front | Front |
| Engine Size | 2171 cc | 4398 cc |
| Engine Cylinders | 6 cylinders | 8 cylinders |
| Engine Type | in-line | V |
| Valves per Cylinder | 4 valves | 4 valves |
| Horse Power | 167 HP | 325 HP |
| Engine RPM | 6500 RPM | 6100 RPM |
| Torque | 210 Nm | 450 Nm |
| Torque RPM | 3500 RPM | 3600 RPM |
| Engine Bore Size | 80 mm | 92 mm |
| Engine Stroke Size | 72 mm | 82.7 mm |
| Engine Compression Ratio | 10.0:1 | 10.5:1 |
| Drive Type | Rear | Rear |
| Transmission Type | Manual | Manual |
| Number of Seats | 5 seats | 4 seats |
| Number of Doors | 5 doors | 2 doors |
| Vehicle Weight | 1670 kg | 1690 kg |
| Vehicle Length | 4810 mm | 4830 mm |
| Vehicle Width | 1810 mm | 1860 mm |
| Vehicle Height | 1450 mm | 1380 mm |
| Wheelbase Size | 2840 mm | 2890 mm |
| Fuel Tank Capacity | 70 L | 70 L |
